1. Field of the Invention
The invention relates to a method for selecting a label from a multiplicity of labels stored in a memory element by handwritten input of a character into a handwritten input apparatus, association of an alphanumeric character with the handwritten input character in a character recognition apparatus, addition of the associated alphanumeric character to an already input character string to produce an extended character string, comparison of the extended character string with the labels stored in the memory element, and selection of one or more of the stored labels using the comparison. The invention also relates to a motor vehicle navigation system.
2. Description of Prior Art
In motor vehicle navigation systems and other appliances, such as travel ticket machines, it is necessary to select a label, such as a place name, from a large number of stored labels. In principle, a label of this kind can be input using a keypad. Often, a keypad of this kind is not provided for reasons of space, however. A touch-sensitive input system, such as a touchpad or a touchscreen, can be used to input characters in handwriting. A handwriting recognition system is used to recognize the input characters, that is to say that an alphanumeric character is associated with the input character. In this context, a distinction is drawn between handwriting recognition systems in which the characters need to be input on the basis of fixed rules and those which allow free input, that is to say with the writer's individual writing style. Users prefer the latter handwriting recognition systems, since there is no need for a prior learning process to learn the input rules for the characters. However, these systems then have the problem of an input character being ambiguous. By way of example, a vertical stroke can be interpreted either as the digit “1” or as the letter “L” (in lower case) or as the letter “I”. A circle can accordingly be interpreted as the letter “O” or as the digit “0”. Similar problems may also arise when inputting a character for the letters “a”, “d” and “q” and others, for example.
To solve this problem of an input character being ambiguous, the alphanumeric characters which are possible for the input character can be presented to the user for manual selection. The user then needs to decide manually, for example, whether the vertical stroke which he has input is to be interpreted as a “1” or as an “L” or an “I”.
In addition, it is possible to infer the appropriate alphanumeric character to some extent from the context of the character input. If a telephone number is being input, for example, then the input of a circle can mean only the digit “0” and not the letter “O”, for example. In addition, it is also possible to preselect, for example manually, that only letters or only numbers are input.
If a handwriting recognition system is used to input destinations in a navigation system, the ambiguity described above can be resolved using neither the context nor a limitation to the input of exclusively letters or numbers, since numbers and letters are permitted equally. Also, manual selection between a plurality of alphanumeric characters which are possible for the input character is inexpedient, particularly in the case of motor vehicle navigation systems, since it increases the complexity of operator control and detains users who are intent on rapid input of the destination.